The optical lens, such as the reader head of the CD player, digital camera, mobile phone camera and optical communication device, is in wide demands. As the high precision molding industry, such as glass molding and injection molding, rapidly progresses, the axis-symmetrical optical components must overlap the optical axis and the rotational symmetrical axis during the manufacturing or system assembly to avoid off-axis aberration errors. As the optical lens is widely applied and the demands on the calibration of optical system assembly, the error checking and estimation is an important issue for manufacturing high precision optical lens.
In the general optical system, if the optical axis of the lens does not coincide with the reference axis, there will be off-axis aberrations in the optical image formed by the optical beam entering the optical system through reflection and refraction; thus, the overall quality of the optical system is compromised. Therefore, currently, the optical components, such as lens, will be calibrated before assembling the optical system.
The approach to confirm the image-forming quality of the conventional optical system is to use high magnification optical system to magnify the focal spot of the object lens of the reader head. With the shape of the spot, the image-forming quality can be analyzed and then the component quality and the aberrations of the optical system can be further analyzed. However, the above optical calibration system is easily affected by the environment and the vibration during calibration because of using the high magnification optical system. In actual application, the vibration problem must be solved with the assistance of a servo control system. Therefore, the system is complicated and more costly.